More than 16,000 Finnish people have had their data leaked on a file-sharing website. Social security numbers, home addresses, telephone numbers and email addresses were among the leaked data.

According to F-Secure CEO Mikko Hyppönen, it is not yet known how the information ended up online, but it looks as though it could have come from an online service where people fill in their information themselves. He suspects that careless handling of information could lie behind the data breach.

Hyppönen fears that the information could be misused, as it could allow people to impersonate somebody else. He says that the authorities have been in touch with the website and had the file removed, and contacted some of those affected.

The data breach came to light on Saturday, and the National Bureau of Investigation (NBI) has begun a criminal investigation. Similar cases are rare in Finland.

Tweets by Mikko indicate that the data dump was published on several servers. As of the time of this posting, it is still available on a server from which it had reportedly been removed.